docs: def get_user_activities(self, username, tournament=1):
          """Get user activities (works for all users!).
  
          Args:
              username (str): name of the user
              tournament (int): ID of the tournament (optional, defaults to 1)
  
          Returns:
              list: list of user activities (`dict`)
  
              Each activity in the list as the following structure:
  
                  * resolved (`bool`)
                  * roundNumber (`int`)
                  * tournament (`int`)
                  * submission (`dict`)
                   * concordance (`bool`)
                   * consistency (`float`)
                   * date (`datetime`)
                   * liveLogloss (`float`)
                   * liveAuroc (`float`)
                   * validationLogloss (`float`)
                   * validationAuroc (`float`)
                  * stake (`dict`)
                   * confidence (`decimal.Decimal`)
                   * date (`datetime`)
                   * nmrEarned (`decimal.Decimal`)
                   * staked (`bool`)
                   * usdEarned (`decimal.Decimal`)
                   * burned (`bool`)
  
          Example:
              >>> NumerAPI().get_user_activities("slyfox", 5)
              [{'tournament': 5,
                'submission': {
                 'validationLogloss': 0.6928141372700635,
                 'validationAuroc': 0.52,
                 'liveLogloss': None,
                 'liveAuroc': None,
                 'date': datetime.datetime(2018, 7, 14, 17, 5, 27, 206042, tzinfo=tzutc()),
                 'consistency': 83.33333333333334,
                 'concordance': True},
                'stake': {'value': Decimal('0.10'),
                 'usdEarned': None,
                 'staked': True,
                 'nmrEarned': None,
                 'date': datetime.datetime(2018, 7, 14, 17, 7, 7, 877845, tzinfo=tzutc()),
                 'confidence': Decimal('0.100000000000000000')},
                 'burned': False
                'roundNumber': 116,
                'resolved': False},
               {'tournament': 5,
                'submission': {'validationLogloss': 0.6928141372700635,
  
                 ...
  
                 ]
  
          """
          query = '''
              query($tournament: Int!
                    $username: String!) {
                userActivities(tournament: $tournament
                       username: $username) {
                  resolved
                  roundNumber
                  tournament
                  submission {
                      concordance
                      consistency
                      date
                      liveLogloss
                      liveAuroc
                      validationLogloss
                      validationAuroc
                  }
                  stake {
                      confidence
                      date
                      nmrEarned
                      staked
                      usdEarned
                      value
                      burned
                  }
                }
              }
          '''
          arguments = {'tournament': tournament, 'username': username}
          data = self.raw_query(query, arguments)['data']['userActivities']
          # filter rounds with no activity
          data = [item for item in data
                  if item['submission']['date'] is not None]
          for item in data:
              # remove stakes with all values set to None
              if item['stake']['date'] is None:
                  del item['stake']
              # parse
              else:
                  utils.replace(item['stake'], "date",
                                utils.parse_datetime_string)
                  for col in ['confidence', 'value', 'nmrEarned', 'usdEarned']:
                      utils.replace(item['stake'], col, utils.parse_float_string)
          # parse
          for item in data:
              utils.replace(item['submission'], "date",
                            utils.parse_datetime_string)
          return data